学习过程中MF－CA3与PP－CA3突触传递效应的变化

CHANGES OF SYNAPTIC TRANSMISSION EFFICIENCY IN THE MF-CA3 AND PP-CA3 PATHWAYS OF RAT HIPPOCAMPUS DUING DISCRIMINATION LEARNING

应用慢性电极埋植技术以电生理学结合行为学的方法，探查在学习过程中大鼠海马ＣＡ３区两种不同输入突触（ＭＦ－ＣＡ３突触和ＰＰ－ＣＡ３突触）的可塑性变化及其相互关系。结果如下：（１）在分辨反应的建立过程中，在ＣＡ３区由ＭＦ诱发（ＭＦ－ＣＡ３）的群体锋电位（ｐｏｐｕｌａｔｉｏｎｓｐｉｋｅ，ＰＳ）和由ＰＰ诱发（ＰＰ－ＣＡ３）的群体锋电位，两者的峰值同步增大，同步达最高水平，且ＰＳ峰值达最高水平先于行为反应达学会标准；（２）在自然消退过程中，两者的ＰＳ峰值也是同步恢复至训练前水平的。结果表明，在ＣＡ３区这两种输入突触的习得性ＬＴＰ的产生和消退都是同步的，提示了它们之间可能具有协同作用。

Electrophysiological and behavioral studies were performed in rat to investigate thechanges of synaptic efficacy of the two inputs of hippocampal CA3 area [Mossy Fiber(MF)-CA3 and Perforant Path (PP)-CA3] during discrimination learning. The resuits showed that: (1) Amplitude of the population spike (PS) of both from MF-CA3and PP-CA3 increased simultaneously with the establishment of conditioned response(CR) and both reached their maxima before CR reached the cirterion of acquisition.(2) During natural extinction of CR, the amplitude of PS of both inputs decreased alsosimultaneously to their per-training level. These results indicated that the learning-dependent long--term potentiation (LTP) in both MF--CA3 and PP--CA3 inputs developedand extinguished synchronously, suggesting that the changes of synaptic efficacy of different inputs of hippocampal CA3 area coordinated during discrimination learning.